Math Symbols in HTML

This page explains how to place various mathematical characters into HTML documents.
A 1999 version of this document is available here and a 2005 version here.
The symbols have been grouped into the following categories:

Update (1 Sep 2009): In this version the Symbol FONT FACE TAG method has been eliminated because they are no longer reliable.Update (19 Mar 2007): Additional character entities

INTRODUCTION
There are several ways to add these symbols to your pages. I will omit consideration of symbols which appear on the keyboard unless, like &, they have a special HTML meaning. Of course, for any symbol, a .gif image can be created and the image displayed using the <img> tag. I will omit consideration of this strategy as well. In the tables below two codes will be given for displaying a character: the HTML numerical code and a special HTML literal code (where available).

Well, how do you use this stuff? The following samples illustrate the use of each code method. To place a symbol in an HTML page or an email message (readable using a web browser) copy and paste the appropriate code into the file (or message) where you want the symbol.

HTML NUMERIC CODE example: to make a left curly bracket {, type &#123;.

HTML LITERAL CODE example: to make a degree symbol °, type &deg;.

One more thing. To form superscripts or subscripts use the <SUP> or <SUB> tags.

SUPERSCRIPT example: to write 2ℵ, type 2<SUP>&alefsym;</SUP>.

SUBSCRIPT example: to write x5, type x<SUB>5</SUB>.

BROWSER TEST: To view symbols with numeric codes above 255 and perhaps some literal code symbols the browser character encoding must be set to unicode (UTF-8).
If the following string of symbols cannot be read, the browser setting needs to be changed.
Upwards arrow (Numeric code: ↑, Literal code: ↑), intersection (Numeric code: ∩, Literal code: ∩)